CHLOROQUINE-INDUCED PRURITUS IN MALARIA FEVER - CONTRIBUTION OF MALARIA PARASITEMIA AND THE EFFECTS OF PREDNISOLONE, NIACIN, AND THEIR COMBINATION, COMPARED WITH ANTIHISTAMINE

Aims Chloroquine treatment of malaria fever, results in a generalized pruritus of unknown mechanism in up to 60% of adult Africans, by contr ast pruritus is unusual in Caucasians following chloroquine use. Metho ds We conducted a double-blind randomized, parallel group study to exa mine and compare the antipruritic effects of promethazine, niacin, pre dnisolone and their combination on pruritus induced by chloroquine, in 28 historical itching patients with parasitologically proven malaria fever. We also evaluated the role of the antecedent malaria parasite d ensity in the severity of chloroquine pruritus intensity; Results The concurrent administration of chloroquine (2.1 g base total dose) with prednisolone caused a statistically significant reduction in the pruri tus AUC (0, 72 h) (P < 0.001 ANOVA) compared with the antihistamine pr omethazine alone. The areas under the pruritus intensity-time curve we re promethazine 105 +/- 28 (units h), niacin 76 +/- 22, prednisolone 2 8 +/- 24, and prednisolone and niacin 34 +/- 17 (P < 0.001 ANOVA). The 95% confidence interval for the difference in the pruritus AUC betwee n prednisolone and promethazine was 8.4 to 145.6 units h. There was a statistically significant and positive correlation between the pruritu s intensity (AUC 0, 72 h) and the malaria parasite load in the itching subjects, not receiving prednisolone (n = 9) (r = 0.73, P = 0.026 ANO VA). Conclusion A single oral dose of prednisolone (10 mg) may be pref erable to the antihistamine promethazine (25 mg) as an antipruritic ag ent for concurrent prescription with chloroquine in individuals predis posed to severe itching. Malaria parasite clearance and clinical ameli oration were unaffected by any of the treatments.